In a Push to Talk (PTT) communication session, a user with a communications device pushes a “Talk” button to transmit voice or other media to one or more other devices participating in the PTT communications session. Each user is able to initiate a transmission if no other communications device is transmitting/speaking, thereby supporting a communications session involving multiple users where each user is able to participate. Cellular telephone systems are incorporating functionality to perform PTT over Cellular (PoC) communication sessions, whereby a user is able to operate a cellular phone in a manner that appears to the user to be a conventional PTT communications session.
PoC communication sessions are sometimes managed by transmission of Session Description Protocol (SDP) and Session Initiation Protocol (SIP) messages between a PoC controller, in conjunction with a Radio Access Network (RAN), and multiple Mobile Subscriber (MS) units.
A standard known as OMA PoC 1.0 (http://www.openmobilealliance.org) focuses primarily on voice services for 1-to-1, group, and chat room call types. As broadband technologies become more prevalent, these simple call types will evolve. Users will desire to share multiple media streams (e.g., voice, music, and video) within the confines of a single PoC session. However, whenever multiple media streams are present, the issue of floor control arises.
In PoC 1.0, floor control for voice is carried out by the Talkburst Control Protocol (TBCP), which is used by the PoC server. The PoC server is a central arbiter and the floor is granted to a single client at a time. Because the voice stream is arbitrated only by the controlling PoC server, the system suffers from the disadvantage that originating clients cannot select how each stream is arbitrated.
Situations can arise where a client may wish to designate one stream in the session to be arbitrated by the controlling PoC server and another stream arbitrated by one of the clients in the session. For instance, a PoC user participating in a group call, in addition to hearing the audio of the current talker, may wish to select the video feed of another group member (who may not be the current talker). Unfortunately, current PoC server arbitration management methods do not support multiple media streams in a single session with independent floor arbitration control for each media stream.
In some communication sessions, certain content is essential for the purpose of the session. For instance, if a session is for discussing a particular piece of video, it is useless to include a user with a device that is not capable of displaying the video. In other cases, content is an enhancement to the conversation, but not necessary. With current PoC systems, originating clients cannot designate which of multiple media streams in the session are mandatory (i.e., all participants must receive) or optional (terminating clients may select the streams they wish to receive).
Additionally, there is no currently existing method for a user in a session to electronically request another user in the same session to initiate a subsequent media stream to the current session (e.g., user 1 requests user 2 to begin transmitting video).
Therefore a need exists to overcome the problems with the prior art as discussed above.